Sidebar: Deciphering the story of a bullet

Steve Mills and David HeinzmannTribune staff reporters

To a medical examiner, the beauty of a bullet wound is that it usually tells a story.

When a bullet enters the body, for instance, pushing into skin just before puncturing it, the projectile scrapes away a little skin. It leaves a round or oval collar of abrasion, like a dark ring, just around the wound.

If a bullet is fired from close range-say, from inside 2 feet-the bullet, gunpowder and hot gases cause tiny cuts on the skin and leave a ring of soot. "Stippling" is the term for the marks left by such contact wounds.

Find those key characteristics and, more likely than not, pathologists say, you have an entrance wound, as well as a good clue to where the shooter was standing when they fired.

At the scene of a shooting, when the bodies are still clothed and bloody, the difference between an entrance and exit wound may not be obvious to the naked eye.

Clarity, however, prevails in the autopsy room or the surgical suite, where unbiased scientific assessment allows a medical examiner or physician to identify where a police officer's bullet entered the body, and even to track that bullet along its path of destruction to its exit.

It starts with X-rays and what medical examiners call an external examination. The doctors look through the clothes, searching for bullet holes, trying to see if soot collected around them.

Working from head to toe, doctors examine the body for wounds and, when they find them, precisely note them on diagrams of the body. They trace the path of the bullet through the body, noting the damage it caused as it tore through tissue and organs and ricocheted off bones. They run dowels through gunshot wounds to show the trajectory of the bullet. They photograph the wounds.

The medical examiner has a narrow task: determining the cause and manner of death. They do not decide if a police shooting was justified or not. In fact, many say they often do not have enough facts to know.